Dispensing of a chemical agent slowly over a period of time is useful in many industries, particularly in the agriculture, railroad and roadway maintenance industries. Conventional application of fertilizers, pesticides and herbicides is time consuming and requires repeated application. Typically, application of these chemical agents is time sensitive for the chemical agent to be effective. Additionally, environmental factors such as rain may wash away the chemical requiring another application within a specified period of time for the chemical to be effective.
Various slow dispensing devices have been developed to release small amounts of fertilizer, pesticides or herbicides over an extended period of time. Some of these devices include biodegradable materials impregnated with the chemical to be dispensed. As the biodegradable material decomposes, the chemical is released. Other devices have dissolved the desired chemical in an elastomeric material at a super saturated concentration causing the chemical to bloom to the surface of the elastomer and be dispensed into the surrounding environment.
Problems associated with such slow dispensing devices include leaching of chemicals and the danger of exposure to the user, fragile carrier systems whereby the carrier material is susceptible to breakage during handling and installation, or conversely, the carrier material is not biodegradable and requires removal and disposal after a period of time.